The dynamic parameters of body protein metabolism are being studied for the ways in which they respond to varying levels of dietary protein and energy intake in adult humans. For this purpose the rates of total body protein synthesis and catabolism are determined following oral administration of 15 N-glycine during a 48-60 hour experimental period. Synthesis and catabolic rates are estimated by means of a simple, one- pool model, described by Picou and Taylor-Roberts. Total body protein synthesis and catabolic rates in adults consuming adequate protein was found to be 2.8 and 2.4g protein/kg body weight/day, respectively. The effects of adequacy of the level of dietary protein intake are currently being studied in normal adults and additional studies have been extended to the effects of therapeutic starvation on these parameters of body protein metabolism in obese subjects. The objective of the research is to determine the ways in which man adapts varying protein and energy intakes.